\(a,-\dfrac{3}{5}.x=\dfrac{9}{25}\)
\(x=\dfrac{9}{25}\div-\dfrac{3}{5}\)
\(x=-\dfrac{3}{5}\)
\(\dfrac{x}{2}=-\dfrac{9}{6}\)
\(\dfrac{x}{2}=-\dfrac{3}{2}\)
\(x=-3\)
\(3,\) \(\dfrac{3}{7}+\dfrac{1}{7}\div x=\dfrac{3}{14}\)
\(\dfrac{1}{7}\div x=\dfrac{3}{14}-\dfrac{3}{7}\)
\(\dfrac{1}{7}\div x=-\dfrac{3}{14}\)
\(x=\dfrac{1}{7}\div-\dfrac{3}{14}\)
\(x=-\dfrac{2}{3}\)
\(4,\) \(-\dfrac{1}{3}\left(\dfrac{1}{7}-x\right)=\dfrac{1}{21}\)
\(\dfrac{1}{7}-x=\dfrac{1}{21}\div-\dfrac{1}{3}\)
\(\dfrac{1}{7}-x=-\dfrac{1}{7}\)
\(x=\dfrac{1}{7}--\dfrac{1}{7}=\dfrac{1}{7}+\dfrac{1}{7}\)
\(x=\dfrac{2}{7}\)
\(5,\) \(\left(\dfrac{2}{3}-x\right)\div\dfrac{5}{6}=-\dfrac{1}{4}\)
\(\left(\dfrac{2}{3}-x\right)=-\dfrac{1}{4}.\dfrac{5}{6}\)
\(\dfrac{2}{3}-x=-\dfrac{5}{24}\)
\(x=\dfrac{2}{3}--\dfrac{5}{24}=\dfrac{2}{3}+\dfrac{5}{24}\)
\(x=\dfrac{7}{8}\)
\(6,\) \(\dfrac{2}{7}-\left(\dfrac{2}{3}+2x\right)=\dfrac{5}{7}\)
\(\dfrac{2}{3}+2x=\dfrac{2}{7}-\dfrac{5}{7}\)
\(\dfrac{2}{3}+2x=-\dfrac{3}{7}\)
\(2x=-\dfrac{3}{7}-\dfrac{2}{3}\)
\(2x=-\dfrac{23}{21}\)
\(x=-\dfrac{23}{21}\div2\)
\(x=-\dfrac{23}{42}\)
